1. Field of the Invention
The present invention relates to a continuity test unit for a connector and more particularly relates to a continuity test unit for protecting a connector and a detector during testing when an overload force is applied to the detector.
2. Description of the Related Art
A conventional continuity inspection apparatus includes a connector holder for mounting a connector that has a housing containing plural terminals, a test section configured to move forward toward and backward away from the connector holder for testing a continuity of the terminals, and a driving mechanism for moving the test section relative to the connector holder between a test position where the test section approaches the connector holder and a rest position where the test section is displaced away from the connector holder.
The test section has a detector at a position corresponding to the terminals contained in the housing. The detector has an outer sleeve and a contact end portion extending from, and elastically movable relative to, the outer sleeve.
During a continuity test, a connector is mounted in the connector holder and the driving mechanism is actuated to move the test section toward the connector holder. The detector comes into contact with the terminals to commence the continuity test. In order to precisely position the contact end portion relative to the terminal, the outer sleeve is rigidly secured to the test section.
However, if the detector is in an abnormal condition in which the contact end portion cannot elastically retract into the outer sleeve, which is rigidly secured to the test section, the detector will push against the terminal, thereby damaging the terminal and/or the detector. Also, since the outer sleeve is rigidly secured to the test section, it is difficult to reuse the test section from one inspection apparatus in another inspection apparatus.
In view of the above problems, an object of the present invention is to provide a continuity test unit that can prevent a detector from breaking a connector being tested, and to reduce costs by allowing for the reuse of a test section.
To achieve the foregoing object, according to the present invention, a continuity test unit for a wire harness connector having a housing containing plural terminals is provided. The continuity test unit includes a connector holder, a test section, and a displacement device. The connector holder is configured to hold a connector in position for testing the continuity of plural terminals contained in a housing of the connector. The test section is configured to move forward toward and backward away from the connector holder. The test section includes a detector opposed to the terminals contained in the housing of the connector held in the connector holder, and a block for supporting the detector. The displacement mechanism is configured to move the test section relative to the connector holder between a test position in which the detector contacts the terminals and a release position in which the detector is spaced away from the terminals, permitting loading and unloading of the connector from the connector holder.
The detector includes an outer sleeve mounted to the block and a contact end portion contained in and extending from the outer sleeve for contacting the terminals. The contact end portion is movable relative to the outer sleeve forward toward the connector holder and backward away from the connector holder. The test section includes a connecting member provided between the outer sleeve of the detector and the block. The connecting member interconnects the detector and the block in such a manner that the detector is disconnected from the block when the detector is subjected to a predetermined load.
Further, in the continuity test unit according to the present invention, the block includes a constraining portion for constraining the outer sleeve of the detector from moving relative to the block toward the connector holder.
Further, in the continuity test unit according to the present invention, the connecting member is removably assembled in the block of the test section.
Further, in the continuity test unit according to the present invention, the detector may be subjected to the predetermined load as a result of an abnormal condition of the detector in which the contact end portion is prevented from moving relative to the outer sleeve. Further, the detector may be subjected to the predetermined load as a result of an abnormal positioning of the terminals contained in the housing of the connector held in the connection holder.
Further, in the continuity test unit according to the present invention, the outer sleeve moves relative to the block away from the connector holder when the detector is subjected to the predetermined load. Further, the test section may include a plurality of the connecting members.
Further, in the continuity test unit according to the present invention, the connecting member is a breakaway element which ruptures upon being subjected to the predetermined load by the detector. The outer sleeve moves relative to the block away from the connector holder when the breakaway element is subjected to the predetermined load and ruptures. The breakaway element may include an opening surrounded by a shoulder portion that is thinner than a remaining portion of the breakaway element, such that the shoulder portion ruptures upon being subjected to the predetermined load by the detector. The test section may include a plurality of the breakaway elements. The plurality of breakaway elements may be formed as a plurality of openings in a substantially flat sheet member having a thickness such that the sheet member ruptures upon being subjected to the predetermined load by the detector. The breakaway element constrains the outer sleeve from moving relative to the block away from the connector holder.
Further, in the continuity test unit according to the present invention, the detector includes a latch sheath portion having a larger diameter than the outer sleeve, and the breakaway element is configured to contact and constrain movement of the latch sheath portion. The block includes a first portion and a second portion defining a substantially enclosed space therebetween, and the breakaway element and the latch sheath portion are located within the substantially enclosed space. The latch sheath portion contacts and is held in the substantially enclosed space by the first portion of the block. The breakaway element contacts and is held in said substantially enclosed space by the second portion of the block.
According to another aspect of the present invention, a continuity test unit for a connector having a housing containing plural terminals is provided. The continuity test unit includes a connector holder, a test section, and a displacement device. The connector holder is configured to hold a connector in position for testing the continuity of plural terminals contained in a housing of the connector. The test section is configured to move forward toward and backward away from the connector holder. The test section includes a detector opposed to the terminals contained in the housing of the connector held in the connector holder, and a block for supporting the detector. The displacement device is configured to move the test section relative to the connector holder between a test position in which the detector contacts the terminals and a release position in which the detector is spaced away from the terminals, permitting loading and unloading of the connector from the connector holder.
The test section includes a breakaway element interconnecting the detector and the block for preventing the detector from moving relative to the block away from the connector holder. The breakaway element interconnects the detector and the block in such a manner that the breakaway element ruptures and the detector is disconnected from the block when the detector is subjected to a predetermined load. The breakaway element may include an opening surrounded by a shoulder portion which is thinner than a remaining portion of the breakaway element, such that the shoulder portion ruptures when the detector is subjected to the predetermined load. The test section may include a plurality of the breakaway elements formed as a plurality of openings in a substantially flat sheet member having a thickness such that the sheet member ruptures when the detector is subjected to the predetermined load.
According to the present invention, a continuity test is carried out by mounting the connector in the connector holder and moving the test section toward the connector holder by the driving device in order to bring the contact end portion of the detector into contact with the terminal in the housing. If an overload force is applied to the detector for any reason, it is possible for the connecting member to absorb the overload force applied to the detector and to protect the detector by releasing the detector from the block. Since the continuity test can be carried out by connecting the outer sleeve of the detector to the block of the test section again, it is possible to reuse the test section, thereby reducing costs. The xe2x80x9cpredetermined loadxe2x80x9d at which the detector is released from the block may be set at substantially one-half of the limit strength of a usual terminal. For example, if the limit strength of the terminal is 98N, the predetermined load may be set to be 49N.
If any impact force is applied to the detector which would cause rebound or bounce back of the detector toward the connector holder, the detector is restrained from bursting out from the predetermined mounting position by the constraining portion of the block. Thus, by preventing the detector from bursting out towards the connector holder, it is possible to protect the terminal, since the detector can come into contact with the terminal at a more suitable position.
According to this invention, since the connecting member is removably assembled in the block, it is possible to carry out the continuity test again by exchanging the connecting member for a new one when any damage occurs to the connecting member. Accordingly, it is possible to protect the terminal and detector at a reduced cost, since the test section can be reused.